Vented fire door



May 24, 1966 c. F. GERHARDT VENTED FIRE DOOR Filed Jan. 22, 1964 /9 Z5 ZO CA ,g5 F GERHARD?" A from/5K5 United States vPatent O 3,252,259 VENTED FIRE DOOR Carl F. Gerhardt, Clarence, NY., assiguor to Dusing and Hunt, Inc., Buffalo, N.Y. Filed Jan. 22, 1964, Ser. No. 339,498

Claims. (Cl. 52-302) This invention relates to re doors and particularly to fire doors of cellular construction having a novel venting arrangement to obviate undue internal gas or air pressure due to thermal expansion of air within the door.

One type of fire door which is knownl in the prior art comprises a core or body portion which is made up' of a large number of short tubular members which are s-tacked or nested so that their opposite ends lie generally in the planes of the opposite faces of the door. 'That is, the individual tubular members have their axes extending perpendicular to ythe faces of the door. The cellular body thus formed is enclosed in various ways by metal framework and metal skin to form a complete door structure. The lire door of -the present invention is of this cellular core construction.

While cellular fire doors of the foregoing general type are thermally efficient, economical in manufacture and of relatively light weight, a major portion of the interior volume of the door is Iair and expansion due to exposure of the door to high temperatures may lead to very harmful results, often explosive in nature. The fire door of :the present invention is so arranged and constructed that undue internal pressures are readily relieved without substantially reducing -the effectiveness of the door as a lire barrier.

The manner in which this pressure relief or venting of the interior of the fire door of the present invention is achieved will become lapparent in the detailed description of a specific embodiment of the fire door of the present invention which is set forth in `the following specification and illustrated in the accompanying drawing. Other objects and advantages will likewise occur to those skilled in the present art from a consideration of this exemplary embodiment but it is to be understood that the fire door thus illustrated and described is by way of example only and that various modifications may be made therein withou-t departing from the principles of the invention the scope of which is limited only as dened in the appended claims.

In the drawing:

FIG. 1 is an elevational view of one form of the fire door of the present invention with portions thereof broken away for added illustration;

FIG. 2 is a bottom plan view of the door of FIG. 1;

FIG. 3 is a cross-sectional view taken approximately on the line III-III of FIG. 1;

FIG. 4 is an elevational view of the structure of FIG. 3; and y FIG. 5 is a fragmentary cross-sectional view taken `approximately on the line V-V of FIG. 2.

Like characters of reference denote like -parts throughout the several figures of the drawing and referring rst to FIG. 1, the door comprises a pair of vertical side channel framingmembers, one of which is designated 11 in FIG. l and the other of which is designated 12 in FIGS. 3 and 4, and top and bottom framing channels designated respectively 13 and 14.

As shown in FIG. 3 the upper and lower channels 13 and 14 are `swaged at their ends -to fit within the vertical channels 11 and 12 and the interlitting channels may be v spot welded or otherwise secured. The remainder of the metallic portion of the structure of the door proper comprises a pair of sheet metal facing or skin members 17 and 18, each of which is flanged at its four marginal edges as indicated at 19 `and 20, respectively, the marginal "ice flanges 19 and 20 lying against the web portions of the several framing channels 11 through 14, as shown in FIG. 5.

Means are provided for forming a honeycomb cellular core structure within the door throughout vthe major portion of i-ts interior. In the present instance such means comprise hexagonal tubes of kraft paper which, merely by way of example, may be of 99-pound stock and measure about one inch across ats. 'Ihe `tubes are designated 22 in the drawing and are of substantially the same length as the distance across the outside surfaces of the several framing channels 11 through 14.

Thus the tubes 22 occupy the space between the facing sheets 17 and 18 as shown in the broken away portions of FIG. 1 but extend only to the inner edges of the framing channels 11 through 14, leaving the spaces between the flanges of the channel members free for air passage. The end surfaces of the tubular members 22 are adhesively securedto the interior surfaces of the sheet metal facing members 17 an'd 18 as by means of an epoxyl resin or other suitable bonding agent.

A very important and significant element in the lire door combination of the present invention resides in the means provided for venting the interior thereof against -the buildup of pressure upon exposure of the door to high tempe'rature. As shown in FIG. 2 a series of openings 2S in the web portion of the bottom framing channel 14 extends in a row between the adjacent edges of the flange portions of the facing sheets 17 and 18.

The openings 25, together with the continuous passage extending about the body of tubular members 22, provide uninterrupted ven-ting to the underside of the door. The openings 25 are concealed at all times but are free to permit escape of hot air and gas from the interior of the door vduring a fire.

Excessive pressure due to thermal expansion of air in the tubular members 22 will burst the adhesive bond and cause the 'facing sheets 17 and 18 to bulge. Without the egress provided by the spaces within the framing channels and the vent passages in the bottom of the door provided by the openings 2S in the botto-m framing channel 14 the door would be apt to blow up due to excessive internal pressure.

Since draft is normally toward the hot or fire side of the d0or, the escaping gas or air from the vent openings 25 wil be drawn into the fire side of the door by natural draft under the door toward the fire.

In a door constructed as aforesaid the free escape of air or gas to the interiors of the framing channels and thence .through the openings 25 limits the aforesaid bulging of the facing sheets to the extremely slight amount required to permit escape of air or gas from the interiors of the tubular members. Thus, the efficacy of the door as a re barrier is not substantially reduced or impaired by the breaking of the Ibond between the ends of the tubular or cellular members and the interiors of the facing sheets due to thermally induced pressure within the tubular or cellular members.

I claim:

1. In a fire door, four channel members joined at their ends to form a door frame, said channel members having their flange portions directed inwardly, a pair of metal facing sheets secured to the exteriors of said channel members to form opposite outer faces of said door, cellular means disposed between said facing sheets to form a door core portion in the area defined by the inner edges of the several channel members, and means bonding said cellular means to said facing sheets forming air entrapped cells, said bonding means rupturing under high pressure whereby said facing sheets bulge outwardly releasing said air, the spaces within said channels forming a continuous marginal air passage about said core portion for receiving said air, and a series of vent openings through the channel member spaced along the bottom of `said door tovent said air passage.

2. In a fire door, four channel members joined at their ends t-o form a door frame, said channel members having their flange portions directed inwardly, a pair of metal facing sheets secured tothe exteriors of said channel members to form opposite outer faces of said door, a plurality of tubular members extending axially between said facing sheets to form a cellular core portion in t-be area within the inner edges of said channels, means bondingV said tubular members to said facing sheets forming air entrapped closed tubes, said bonding means rupturing under high pressure whereby said facing sheets bulge outwardly releasing s aid air, the spaces within said channels forming a continuous marginal air passage about said core portion for receiving said air, and a series of vent openings through the channel member spaced along the bottom of said door to vent said air passage.

3. In a re door, four channel members joined at their ends to form a door frame, said channel members having t-heir flange portions directed inwardly, a pair of metal facing sheets secured t-o the exteriors of said channel members to form opposite outer faces of said door, and a plurality of tubular members extending axially between said facing sheets to form a cellular core portion in the area within the inner edges of said channels, the end faces of said tubular members being adhesively secured to the inner surfaces of said facing sheets forming air entrapped closed tubular members, said adhesive rupturing under high pressure whereby said facing sheets bulge outwardly releasing said air, the spaces within said channels Iforming a continuous marginal air passage about said core portion for receiving said air, and a series of vent openings through the channel member spaced along the bottom of said door to Vent said air passage.

4. In a re door, four channel members joined at their ends to form a door frame, said channel members having their flange portions directed inwardly, a pair of metal facing sheets secured to the exteriors of said channel members to form opposite faces of said door, a plurality of polygonal tubular members extending between said facing sheets to form a honeycomb core portion for said door in the area defined by t-he inner edges of the several channel members, means bonding said tubular members to said facing sheets forming air entrapped closed tubes, said bonding means rupturing under high pressure whereby said facing sheets bulge outwardly releasing said air, the spaces within said channels forming a continuous marginal air passage about said door for receivingy said air, and a series of vent openings spaced along the bottom of said door to vent said air passage.

5. In a tire door, four `channel members joined at their ends to form a door frame, said channel members having their flange portions directed inwardly, a pair of metal facing sheets secured to the exteriors of said channel members to form opposite faces of said door, a plurality of hexagonal tubular members extending between said facing sheets to form a honeycomb core portion for said door in the area defined by the inner edges of the several channel members, the ends of said hexagonal tubular members being adhesively secured to said facing sheets forming air entrapped closed tubular members, said adhesive rupturing under high pressure whereby said facing sheets bulge outwardly releasing said air, the spaces within said channels forming a continuous marginal air passage about said door for receiving said air, and a series of vent openings spaced along the bottom of said door to vent said air passage.

References Cited by the Examiner UNITED STATES PATENTS 2,765,056 10/1956 Tyree 189-46 2,787,345 4/1957 Soubier et al. 189-46 2,996,161 8/1961 Etling 189-46 HARRISON R. MOSELEY, Primary Examiner.

K. DOWNEY, Assistant Examiner. 

1. IN A FIRE DOOR, FOUR CHANNEL MEMBERS JOINTED AT THEIR ENDS TO FORM A DOOR FRAME, SAID CHANNEL MEMBERS HAVING THEIR FLANGE PORTIONS DIRECTED INWARDLY, A PAIR OF METAL FACING SHEETS SECURED TO THE EXTERIORS OF SAID CHANNEL MEMBERS TO FORM OPPOSITE OUTER FACES OF SAID DOOR, CELLULAR MEANS DISPOSED BETWEEN SAID FACING SHEETS TO FORM A DOOR CORE PORTION IN THE AREA DEFINED BY THE INNER EDGES OF THE SEVERAL CHANNEL MEMBERS, AND MEANS BONDING SAID CELLULAR MEANS TO SAID FACING SHEETS FORMING AIR ENTRAPPED CELLS, SAID BONDING MEANS RUPTURING UNDER HIGH PRESSURE WHEREBY SAID FACING SHEETS BULGE OUTWARDLY RELEASING SAID AIR, THE SPACES WITHIN SAID CHANNELS FORMING A CONTINUOUS MARGINAL AIR PASSAGES ABOUT SAID CORE PORTION FOR RECEIVING SAID AIR, AND A SERIES OF VENT OPENINGS THROUGH THE CHANNEL MEMBER SPACED ALONG THE BOTTOM OF SAID DOOR TO VENT SAID AIR PASSAGE. 